Metal deactivators for hydrocarbon oils



United States PatentOfifice 2,696,423 Patented Dec. 7, 1954 DonalcLR.- Stevens, .Wilkinsbnrg Pa assignor to Gulf Research- & Development Company, Pittsburgh; Pa, a corporation of Delaware L No Drawing. Application October 1, 1951,

Serial No. .249,215

18" Claims. (Cl'. '44"-'-63) This invention relates to hydrocarbon compositions and methods for. preparing the same.-

Among; the problems related to -the field of :hydrocarbon oilsis that of 'oxid'ation and' gum formation. 1 Hy drocarbonoils. such as gasoline/kerosene, diesel fuels, fuel oils, transformer oils, turbine oils, etc. undergo. gum formation with a resultant adverse effect upon the market abilityiof the hydrocarbon oil; For example; the problem of 'gum formation assumes great. importance in t the field of gasoline fuels. Thus, when gum formation h'asoccurred to any considerable extent, the value of the gasoline asra fuel for"internaliicombustiorr engines-is greatly I'edUCBdJ' Gum'formatio'n. is ithel'resultuofvthe oxidation of unsaturated hydrocarbons which :may rbepresent'in the hydrocarbon. oil,z-and is. effectedrfrom-J contact of -the hydrocarbon-oil with air. Such deleterious oxidation: is

mostoften" encountered :with-gasolines, and. in particular with cracked, reformed, and polymerrgasolines 'which contain relatively high concentrations of monoolefins and somewhat smaller concentrations'of other unsaturatedihydrocarb'ons" such as 'dio'lefinsr Accordingly," 'it is necessary 'to minimize or' prevent the above-mentioned oxidation reactions. This has been accomplished by the addition to e thehydrocarbon oils of so calleds'antioxidants'. or oxidation inhibitors. For ex ample-,1 antioxidantslsuch'xas 2,6-di t butyl-4-methylphenol; 2,4,6 tri tbutylphenol; hydroquinone; alpha -naphthol; bis(2rhydroxy-3-t-butyl-5-methyl-phenyl) methane; hardwood tar distillate; cathechol; n-butyl-p-aminophenol; iso

butyli-p-aminophenol; di butyl p phenylene diamine; benzyl-p-aminophenol; di-benzyl-p aminophenol; alphanaphthylaminep 2 t bu't-yl-4-methoxyphenol -(Sustane); phenyl-ailphaf-naplrthylaminehave beenaddedto gasolines.

In-addition to the prevention of oxidation reactions,-

many hydrocarbon oils requiresomewformof sweetening treatmentfor the conversiomof.mercaptansto organic. sulfides, and/or removal of sulfur. This-is particularly true inithe case vof gasolinesn The-sweetening treatmentimproves thelodorofthe gasoline and producesa product.

having a negative doctor test. The sodium plumbite or doctor process, as well as theahypochlorite sweetening process have been used for this purpose for many years. However, during recent years, the so-called-copper-sweetening process has found Wide use; In' thisv process the gasolineis sweetened .through 'contact'with a copper-con taining-"reagent such ascupric chloride; Asa result'of' this treatment the sweetened gasoline usually contains smallamounts-of copper'and/ or copper compoundswhich have a catalytic effect on oxidation reactions'such -as gum formation. Because of the presence ofthe copper and its. resultant catalytic efiect ondeleterious oxidation reactions the formation of gum is.accelerated, and its yield iincreased over and beyond thatwhieh would otherwise-occurin the gasoline.

Moreover, even hydrocarbonoils'which have not undergone copper sweetening may contain gum-catalyzing" metals: and metallic compoundsasthe result of contact witl'ijsuch.metalslduringthecourse of refining, storing; Thusthe hydrocarbon oilsmay contain minute amounts ofsuch metals-asacop; per,-iro n, cobalt,fnickel and the likeL-and their compounds.-

shipping; and usageoperations.

whichare. oxidation catalysts. 1 I p t The deleterious gum-catalyzing effect. of' the aforementioned metals cannot eifectively be.counteracted by the addition; of conventional antioxidants.' Thus, while-in.

certain cases it is possible to'add' a sutiicient'amount of an antioxidant Y to: a a gum-forming hydrocarbon oil to overcome the effect of a gum-catalyzingmetal the efticiency ofuthez' antioxidant undersuch-conditions is so greatly diminishedthat very large amounts of it are necessary, and the'advantagegainedis seldom worth the cost of the increasedquantity of anti'oxidantrequired. Moreover, while it is sometimes possible to remove the gumcatalyzingwmetalby purification, thisis usually too costly tobe practicable and is frequently impossible.

The present invention is directed towards stable-hydro. carbon oil compositions in which thepossibility of gum formation is obviated. 1 Thus; the compositions'of my invention comprise ahydrocarbon oil normally subject to catalyzed gum formation in the presence of a gum catalyzing metal and additionallycontaining in an: amount sufficient to suppress the gum-catalyzing effect of the gum-catalyzing metala relatively minor amount of -a compound having the formula:

whereinR represents a radical selected from-thegroup consistingof hydrogen, alkyl, alkenyL aryl, aralkyljand acyltadicals- In a preferred" embodiment-the compositions of my invention comprise a gum-forming-gasoline containing a gum-catalyzing metal and additionally containing as a suppressor of the metals gum-catalyzing effect a relatively minor amount of' the afore-mentioned compound. This compound is effective as a= metal deactivator in gasoline in very minor amounts, preferably of the order of 0.00003 weight'per cent to 0.0015 weight per cent or about one-tenth to five pounds of metal deactivator perlthousandbarrels of gasoline. Furthermore, my invention also comprises the process for suppressing; the effect of gum-catalyzing metals in gum-forming. hydrocarbon oils, preferably'in gum-forming gasolines. This is accomplished-by.incorporating a minor amount ofthe' aforeamentionedtype compound in the gum-forming-hydrocarbon. oil. p

I shall illustrate the compositions and'process of my invention by disclosing-their application to gum-forming gasolines. However, it is to .be understood that they are:

activatorsemployed in accordance withmy'inventio'n' are advantageously added-to metal catalyst-contaminated gasollnes which contaln conventionalantioxidants Thepresence ofthese antioxidants "is desirable to prevent'or minimize the oxidation which would normally occur even' were the gum-catalyzing metal absent from the gasoline. It is to be noted that the metal deactivators employed in the compositions of my invention have a diiferent effect fromthat of conventionalantioxidants. 1 Thus, the. anti oxidant is especially effective for the deleterious oxidation reactions whichnormallvoccur; whereas themetal de-.

activators employed in: my invention are specific sup' pressors of the gum-catalyzing eifect ofa gum-catalyzing metal which may be present. Weresuch a metal absent, thegasoline mother-"hydrocarbon oil' would be. rendered stable toair' oxidationby the antioxidant; Accordingly;

the 'metal deactivators employed 'in' my invention are effective suppressors of the? gum-catalyzingeifect of'metal' catalysts in gasolines or' other hydrocarbon oils .where' no antioxidant is employed, and also in gasolines or other hydrocarbon'oilsxcontaining antioxidants. Inthe lattercase, the metal deactivatorrendersit possible to effectively" and economically stabilize the gasoline or'other hydrocarbon oil by means of the antioxidant without employing the largeamounts of antioxidant which would. otherwise be 'ne'cessaryto overcome the catalytic actionof the metal.

In this manner the metal deactivator increases the eificiency of the antioxidant.

The gasoline component employed in the preferred embodiment of my invention can be obtained from any of the sources employed for the derivation of gasolines. Thus, the gasoline may be straight run gasoline, natural gasoline, cracked gasoline, reformed gasoline, polymer gasoline or synthetic gasoline. Since the straight run and natural gasolines do not often contain appreciable quantities of gum-forming constituents, it is with the latter four types of gasoline that my invention is most useful. By cracked gasoline is meant gasoline obtained through the cracking or decomposition of higher boiling petroleum hydrocarbon fractions such as gas oil. By reformed gasoline is meant gasoline obtained from the isomerization and reforming of relatively low-boiling liquid hydrocarbons such as naphtha. By polymer gasoline is meant gasoline obtained from the polymerization of low-boiling hydrocarbons such as C4 hydrocarbons. By synthetic gasoline is meant the gasoline obtained from the so-called Fischer-Tropsch synthesis in which gasoline is formed from the reaction between carbon monoxide and hydrogen. In addition to the afore-mentioncd types of gasolines, gasolines from other sources such as the destructive hydrogenation of high-boiling hydrocarbon constituents like high-boiling liquid petroleum hydrocarbons, coal or lignite; and also gasolines obtained from shale sources can be used.

The finished gasoline compositions of my invention may also contain other additives such as antiknock additives like tetraethyl lead, dyes, etc.

The metal deactivators of the type herein involved comprise a compound having the formula:

I1 II H o-omon wherein R represents a radical selected from the group consisting of:

(a) Hydr0gen.-In this case the compound is kojic acid or Z-hydroxymethyl-S-hydroxy-1,4-pyrone.

(b) Alkyl radicals-Preferably an alkyl radical having from 1 to 20 carbon atoms such as methyl, butyl, tertiary butyl, cyclopentyl, amyl, isoamyl, cyclohexyl, heptyl, octyl and cetyl.

(c) Alkenyl radicals.Preferably an alkenyl radical having from 1 to 20 carbon atoms such as vinyl, allyl, l-butenyl, 2-butenyl, 1,3-butadienyl, l-pentenyl, 3-hexenyl, 2,4-hexadienyl, 2-octenyl, and Z-hexadecenyl.

(d) Aryl radicals which may or may not contain alkyl sabstituents.Preferably an aryl radical having not more than 20 carbon atoms such as phenyl, diphenyl, naphthyl, tolyl, cumyl and duryl.

(e) Aralkyl radicals.Preferably an aralkyl radical having not more than 20 carbon atoms such as benzyl, cuminyl, and on mesityl.

(f) Acyl radicals.Preferably an acyl radical having from 1 to 20 carbon atoms such as acetyl, caproyl, 2-ethylhexanoyl, lauroyl, stearoyl, oleoyl, benzoyl, cumoyl and the naphthenic acid type acyl radicals derived from naphthenic acids having a molecular weight of less than about 350.

Examples of these metal deactivators include kojic acid; 2-methoxymethyl 5 hydroxy-l,4-pyrone; 2-benzyloxymethyl-S-hydroxy-l,4-pyrone; Z-phenoxymethyl 5 hydroxy 1,4 pyrone; 2-lauroyloxymethyl-S-hydroxy-1,4- pyrone; 2-oleoyloxymethyl 5 hydroxy 1,4 pyrone; 2-(Z-ethylhexanoyloxymethyl)-5-hydroxy-1,4-pyrone; the naphthenic esters of kojic acid wherein the naphthenic acid constituents have molecular weights of less than 350; 2-cumoyloxymethyl-S-hydroxy-1,4-pyrone; and 2-benzoyloxymethyl-S-hydroxy-1,4-pyrone.

In order to show the eifect of the metal deactivators of my invention on a gum-forming metal catalyst such as in the case of copper-catalyzed gum formation and oxidation in a copper-sweetened gasoline, the following examples are given:

Example I A copper-sweetened gasoline stock derived from a mixture of straight run and catalytically cracked gasoline Good 0.05

Copper, p. p. m. 0.31

Distillation, gasoline, ASTM D8646:

Over point, F. 111 End point, F. 367 10% evaporated at F. 132 50 204 305 Recovery, per cent 98 Federal Specifications VVL791D.

The acid heat is determined by diluting 75 ml. of gasoline with 75 ml. of naphtha (the nap tha having an acid heat of less than 6.0) in a vented 250 ml. flask containing a Fahrenheit thermometer. 30 ml. of 93-95 per cent sulfuric acid are added to the mixture. The temperature of the mixture is noted as soon as the acid has been added. The flask is then shaken vigorously for '2 minutes. At the end of this shaking period, the temperature is noted again. The difference between the two temperatures is multiplied by 2, and the acid heat value for 150 ml. of the naphtha subtracted from this number. The remainder constitutes the acid heat of the gasoline in degrees Fahrenheit. was employed as the gum-forming gasoline. A commercial gasol1ne antiox1dant known as Du Pont Antioxidant No. 22 which comprises N,N-di-sec-butylphenylenediamine was added to the gasoline stock in a concentration of one pound per one thousand barrels, about 0.0003 weight per cent. ThlS resulted in an improvement in the copper dish gum and oxygen stability characteristics of the mixture, these being: Cogper dish gum, mg./ cc., Method 330.12,

t 2 Oxygen stability, 212 F., min. ASTM D52546 225 Kojoic acid was added in varying concentrations to the afore-mentioned copper-sweetened gasoline stock containing the antioxidant. The copper dish gum and oxygen stability characteristics of the resulting compositions are as follows:

Kojic acid concentration (lb/1,000 bbl. of

gasolmestock) 0.25 0.50 1.0 2.0

OopperD1shGum,M 1000 Method330.12,

Govt Oxygen Stability, 212 F., Min. ASTM D525- As can be seen from the foregoing, the addition of a minor amount of kojic acid resulted in a striking improvement in copper dish gum and oxygen stability characteristics for the gasoline composition, even though the gasoline contained a commercial antioxidant.

Example I] The effect of the addition of 2-lauroyl-oxymethyl-5- hydroxy-1,4-pyrone on the copper dish gum and oxygen stability characteristics for the copper-sweetened gasoline containing Du Pont N0. 22 antioxidant set forth in Example I is as follows:

2-lauroyloxy-methy1-5-hydroxy-1,4-pyrone (lo/1,000 bbl. gasoline) 0.25 0. 50 1. 0 2.0

Copper D1sh Gum, Mg./l00 cc. Method 330.12,

Govt Oxygen Stability, 212 F., Min. ASTM While the improvement in copper dish gum specificatrons for the compositions containing 2-lauroyloxymethyl-S-hydroxy-1,4-pyrone is not'quite as striking as illustrative'wanm:the substitution of other-hydrocarbon oils: which: arezsusceptible tor gum formation in 'the presence-:of'agum catalyzing.-metalr is meant to be included.

Furthermorwother gasolines having-similar properties tothose heretoforezsetrforthleanibe utilized. Inaddition other antioxidants, the use of which is readily apparent to one skilled inthe =artg' can besubstituted for those mentioned hfil'fiiihzau The compositions of myinvention are possessed of superiormoxidation stability andmlowered gum-forming characteristics Thus, .in the 1 case er gasoline's, they comprise superior motor fuels.

In the appended claims, the expressions gumcatalyzing metal and copper are to be construed as meaning the gum-catalyzing metallic element such as nickel, iron, cobalt, or copper, and also as including gumcatalyzing compounds of said metals such as iron chloride, cupric chloride, etc., since even in such compounds it is the metallic component of the compound which catalyzes the gum formation.

I claim:

1. A composition comprising in combination a hydrocarbon oil normally subject to catalyzed gum formation in the presence of a gum-catalyzing metal and additionally containing in an amount sufficient to suppress the gum-catalyzing effect of the gum-catalyzing metal a relatively minor amount of a compound having the formula:

l Ho0 CH HG ii-CHzOR wherein R represents a radical having not more than carbon atoms selected from the group consisting of hydrogen, alkyl, alkenyl, aryl, aralkyl, and acyl radicals.

2. A composition comprising in combination gumi forming gasoline containing a gum-catalyzing metal in an amount sufficient to have a catalytic effect on gum formation and additionally containing as a suppressor of said catalytic effect, a relatively minor amount of a compound having the formula:

CH H i l-011203.

Hi3 CH2OR wherein R represents a radical having not more than 20 carbon atoms selected from the group consisting of hydrogen, alkyl, alkenyl, aryl, aralkyl, and acyl radicals.

4. A composition comprising in combination gumforming gasoline containing an amount of copper suffi- 6 cient -to have a: catalytic effect-on guii'1' forrnatiom-and also contain-ing in anamount suflicient to bea sup pressor 'of 'said catalytic effect; kojic acid-.--

5. A composition comprising. in combination "gum forming gasoline :contaihirig an amount of 'copper sufii cient to have acatal'ytic effect on' gum' format-ionand also containing, in an amountsufiicient to be 'a suppressor of said catalytic eflect, '2-lauroylortymethyl- S-hydrdxy 1,4-pyronen 6. A composition comprising in-combinatiion gumforming gasoline containing 3 an amount of coppel suf ficient to have a catalytic .effect'on gum 'formation-and also containingp in an amount sufficientto be" a sup-f pressor of saidcatalytic effect; -2-oleoyloxyrnethyl-5'-liy drox=y- 1,4-pyro'ne; I

7. A composition comprising in combination gunr forming gasoline containing an amount. of copper sufli cient to have a catalytic effect on' gum"formation-and also containingyinan amount sufficient-to -be a-suppres-' sor of saidcatalytic effect; Z-(Q-ethylhiranoyloiy methyl)- 5-hydroxy 1,'4-pyrone:-

8. A composition comprising in combination gumforming gasoline containing an amount of copper sufficient to have a catalytic effect on gum formation and also containing, in an amount sufficient to be a suppressor of said catalytic effect, the naphthenic acid esters of kojic acid wherein the naphthenic acid constituents have molecular weights of less than 350.

9. A composition comprising in combination gumforming gasoline containing an amount of copper sufficient to have a catalytic effect on gum formation and also containing about 0.00003 weight per cent to 0.0015 weight per cent of kojic acid.

10. The method for treating a hydrocarbon oil normally subject to catalyzed gum formation in the presence of a gum-catalyzing metal which comprises incorporating into said hydrocarbon oil in an amount sufiicient to be a suppressor of the gum-catalyzing effect of thlell gum-catalyzing metal, a compound having the form a:

wherein R represents a radical having not more than 20 carbon atoms selected from the group consisting of hydrogen, alkyl, alkenyl, aryl, aralkyl, and acyl radicals.

12. A method for treating a gum-forming gasoline containing a metal in an amount sufficient to have a catalytic effect on gum formation which comprises incorporating into said gasoline about 0.00003 weight per cent to 0.0015 weight per cent of a compound having the formula:

wherein R represents a radical having not more than 20 carbon atoms selected from the group consisting of hydrogen, alkyl, alkenyl, aryl, aralkyl, and acyl radicals.

13. A method for treating a gum-forming gasoline containing an amount of copper suflicient to have a catalytic effect on gum formation which comprises incorporating into said gasoline in an amount suflicient to be a suppressor of said catalytic effect, kojic acid.

14. A method for treating a gum-forming gasoline containing an amount of copper suflicient to have a catalytic efiect on gum formation which comprises incorporating into said gasoline, in an amount sufficient to be a suppressor of said catalytic effect, 2-1auroyloxymethyl-S-hydroxy-1,4-pyrone.

15. A method for treating a gum-forming gasoline containing an amount of copper sufficient to have a catalytic eifect on gum formation which comprises incorporating into said gasoline, in an amount suificient to be a suppressor of said catalytic efiect, 2-oleoyloxymethyl-S-hydroxy-1,4-pyrone.

16. A method for treating a gum-forming gasoline containing an amount of copper sufficient to have a catalytic efiect on gum formation which comprises incorporating into said gasoline, in an amount sufficient 20 Number 8 to be a suppressor of said catalytic effect, 2-(2-ethylhexanoyloxymethyl) -S-hydroxy-1,4-pyrone.

17. A method for treating a gum-forming gasoline containing an amount of copper sufficient to have a catalytic efiect on gum formation which comprises incorporating into said gasoline, in an amount sufiicient to be a suppressor of said catalytic effect, the naphthenic acid esters of kojic acid wherein the naphthenic constituents have molecular weights of less than 18. A method for treating a gum-forming gasoline containing an amount of copper suflicient to have a catalytic effect on gum formation which comprises incorporating into said gasoline about 0.00003 weight per cent to 0.0015 weight per cent of kojic acid.

References Cited in the file of this patent UNITED STATES PATENTS Name Date 2,474,227 Coleman et al. June 28, 1949 

1. A COMPOSITION COMPRISING IN COMBINATION A HYDROCARBON OIL NORMALLY SUBJECT TO CATALYZED GUM FORMATION IN THE PRESENCE OF GUM-CATALYZING METAL AND ADDITIONALLY CONTAINING IN AN AMOUNT SUFFICIENT TO SUPPRESS THE GUM-CATALYZING EFFECT OF THE GUM-CATALYZING METAL A RELATIVELY MINOR AMOUNT OF A COMPOUND HAVING THE FORMULA: 